Semiconductor packaging and manufacturing method thereof

ABSTRACT

The present disclosure provides a semiconductor package, which includes a substrate, a passivation layer, a post-passivation interconnect (PPI) having a top surface; and a conductive structure. The top surface of the PPI includes a first region receiving the conductive structure, and a second region surrounding the first region. The second region includes metal derivative transformed from materials made of the first region. The present disclosure provide a method of manufacturing a semiconductor package, including forming a first flux layer covering a portion of a top surface of a PPI; transforming a portion of the top surface of the PPI uncovered by the first flux layer into a metal derivative layer; removing the first flux layer; forming a second flux layer on the first region of the PPI; dropping a solder ball on the flux layer; and forming electrical connection between the solder ball and the PPI.

CROSS REFERENCE

This application claims the benefit of prior-filed application Ser. No.14/077,528, filed Nov. 12, 2013, under 35 U.S.C. 120.

FIELD

The present disclosure relates to a semiconductor packaging structure.

BACKGROUND

Wafer Level Packaging (WLP) refers to the technology of packaging anintegrated circuit (IC) at a wafer level, instead of the traditionalprocess of assembling the package of each individual die on individualpackages. One feature of the WLP is that the resulting integratedcircuit package is practically the same size as the individual packagediced. Furthermore, WLP provides a streamlining of the semiconductormanufacturing process from start to customer shipment.

Soldering structures are well-adopted in WLP for external electricalconnections. These range from hand-soldering methods to machinesoldering methods. It is well-known to use a flux material with thesoldering material. The flux material satisfies a number of functions.Generally a main function of the flux material is to ensure thatconductive material of a first component, for example a supportsubstrate such as a printed circuit board (PCB) interconnects well withgood electrical conduction across the solder interconnect to a secondcomponent such as an electronic component.

To form a successful interconnection it is often necessary to apply aflux material. A number of different alternatives have been used. It isknown for example to include a solid flux material within the solderingmaterial. Generally such a soldering material would then be provided ina wire or other such solid form which would incorporate a core of fluxmaterial running through the solder. As the solder melts upon heating,the flux is activated, and the resulting interconnect formed if thesoldering process is of an acceptable standard. It is also known to usesolder paste materials. Solder pastes are generally homogenous, stablesuspensions of solder particles in a flux medium material.

Reflow soldering is used in the automated manufacture of PCB's, whereinelectronic components are surface mounted on PCB's to which a solderpaste material has previously been applied by a method such as screen orstencil printing or dispensing. The PCB is then subjected to asufficiently high temperature, to cause the solder to liquefy and tojoin the components in place on the PCB. The heat can be supplied by,for example, infrared, heated conveyor belt or convective means.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale.

In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 is a cross sectional view of a portion of a semiconductor packageaccording to some embodiments of the present disclosure;

FIG. 2A is a top view of a portion of a semiconductor package accordingto some embodiments of the present disclosure;

FIG. 2B is a top view of a portion of a semiconductor package accordingto some embodiments of the present disclosure;

FIG. 3A to FIG. 3C is a cross sectional view of a portion ofsemiconductor packages prepared by the manufacturing methods describedherein according to some embodiments of the present disclosure;

FIG. 4A to FIG. 4C are cross sectional views of a portion ofsemiconductor packages prepared by the manufacturing methods describedherein according to some embodiments of the present disclosure;

FIG. 5A to FIG. 5C are cross sectional views of a portion ofsemiconductor packages prepared by the manufacturing methods describedherein according to some embodiments of the present disclosure;

FIG. 6A to FIG. 6C are cross sectional views of a portion ofsemiconductor packages prepared by the manufacturing methods describedherein according to some embodiments of the present disclosure;

FIG. 7A and FIG. 7B are cross sectional views of a portion of asemiconductor package prepared by the manufacturing method describedherein according to some embodiments of the present disclosure;

FIG. 8A and FIG. 8B are cross sectional views of a portion of asemiconductor package prepared by the manufacturing method describedherein according to some embodiments of the present disclosure;

FIG. 9A and FIG. 9B are cross sectional views of a portion of asemiconductor package prepared by the manufacturing method describedherein according to some embodiments of the present disclosure; and

FIG. 10 to FIG. 16 are cross sectional views of a portion ofsemiconductor packages prepared by the manufacturing methods describedherein according to some embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

This description of illustrative embodiments is intended to be read inconnection with the accompanying drawings, which are to be consideredpart of the entire written description. In the description ofembodiments disclosed herein, any reference to direction or orientationis merely intended for convenience of description and is not intended inany way to limit the scope of the present invention. Relative terms suchas “lower,” “upper,” “horizontal,” “vertical,”, “above,” “below,” “up,”“down,” “top” and “bottom” as well as derivative thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) should be construed torefer to the orientation as then described or as shown in the drawingunder discussion. These relative terms are for convenience ofdescription only and do not require that the apparatus be constructed oroperated in a particular orientation. Terms such as “attached,”“affixed,” “connected” and “interconnected,” refer to a relationshipwherein structures are secured or attached to one another eitherdirectly or indirectly through intervening structures, as well as bothmovable or rigid attachments or relationships, unless expresslydescribed otherwise. Moreover, the features and benefits of theinvention are illustrated by reference to the preferred embodiments.Accordingly, the invention expressly should not be limited to suchpreferred embodiments illustrating some possible non-limitingcombination of features that may exist alone or in other combinations offeatures; the scope of the invention being defined by the claimsappended hereto.

In the drawings, like reference numbers are used to designate like orsimilar elements throughout the various views, and illustrativeembodiments of the present invention are shown and described. Thefigures are not necessarily drawn to scale, and in some instances thedrawings have been exaggerated and/or simplified in places forillustrative purposes only. One of ordinary skill in the art willappreciate the many possible applications and variations of the presentinvention based on the following illustrative embodiments of the presentinvention.

Conventional four-L (4L) solder ball mount operation includes fourlithography operations, namely a first lithography for a firstdielectric layer, a second lithography for a post-passivationinterconnect (PPI) layer, a third lithography for a second dielectriclayer or a passivation layer, and a fourth lithography for a under bumpmetallization (UBM) layer. After the formation of the UBM layer, aconductive bump or a solder ball is disposed thereon to complete anexternal connection structure.

In the above-mentioned 4L external connection structure, a pattern ofthe second dielectric layer and the UBM create a concave structure toaccommodate the subsequent conductive bump or the solder ball. Underthis circumstance, the position of the conductive bump or the solderball is confined within an area formed by the UBM even after a reflowoperation. However, the manufacturing cost for the 4L externalconnection structure exceeds the alternative 2L external connectionstructure, and hence the current trend appears to adopt the 2L externalconnection structure in which only a first dielectric layer and a PPIlayer is used.

In the 2L external connection structure, lack of the solder ballconfinement causes ball shift and proliferate problems such as lowpackaging yield and low reliability. Ball shift phenomenon causes theelectrical path to be cutoff and the contamination of the adjacentelectrical trace distribution. Moreover, a minor ball shift can result amechanically weak spot at a triple interface between the solder ball,the molding compound, and the ambient or underfill. Said weak spoteasily produces crack which is inclined to propagate across the solderball.

Some solutions are provided to resolve the ball shift problem in a 2Lsetting. For example, a recess is first formed in a PPI layer in orderto accommodate the solder ball. Nevertheless, not only the additionalpatterning of the PPI layer produces extra cost, the ball shift problemsremain to damage the reliability of the packaged devices. Someembodiments of the present disclosure provide a semiconductor packagestructure under a 2L setting, wherein a surface treatment is utilized tospatially confine the solder all disposed on the PPI. A portion of thesurface of the PPI is transformed into metal derivative regions therebyavoid the contamination of the solder ball, and hence the spatialconfinement of the solder ball is achieved. Some embodiments of thepresent disclosure also provide methods for manufacturing thesemiconductor package structure under a 2L setting.

In describing and claiming the present disclosure, the followingterminology will be used in accordance with the definitions set forthbelow.

As used herein, “flux” refers to substances facilitating solderingprocesses. In some embodiments, the flux contains reducing agent such ascharcoal. In some embodiments, the flux contains corrosive materials. Insome embodiments, the flux reduces surface tension of the molten solderand causes it to flow and wet a work piece more easily. In someembodiments, the flux is rosin-based.

As used herein, “vapor deposition” refers to process of depositingmaterials on a substrate using a vapor phase of a material to bedeposited or a precursor of the material. Vapor deposition processesinclude any process such as, but not limited to, chemical vapordeposition (CVD) and physical vapor deposition (PVD). Examples of vapordeposition methods include hot filament CVD, rf-CVD, laser CVD (LCVD),conformal diamond coating processes, metal-organic CVD (MOCVD),sputtering, thermal evaporation PVD, ionized metal PVD (IMPVD), electronbeam PVD (EBPVD), reactive PVD, atomic layer deposition (ALD), plasmaenhanced CVD (PECVD), high density plasma CVD (HDPCVD), low pressure CVD(LPCVD), and the like.

As used herein, “molding compound” refers to a compound formed withcomposite materials. A molding compound may include epoxy resins,phenolic hardeners, silicas, catalysts, pigments, mold release agents,or the like. Material for forming a molding compound has a high thermalconductivity, a low moisture absorption rate, a high flexural strengthat board-mounting temperatures, or a combination thereof.

As used herein, “electrical interconnects” refers to conductive lines orfilms routed inside the IC structure over and around the die or dies. Insome embodiments, the electrical interconnects are redistribution layers(RDL). The RDLs are used for a fan-in or a fan-out process. In someembodiments, the electrical interconnects are formed with a conductivematerial such as gold, silver, copper, nickel, tungsten, aluminum,and/or alloys thereof.

As used herein, a “patterning” or “patterned” is used in the presentdisclosure to describe an operation of forming a predetermined patternon a surface. The patterning operation includes various steps andprocesses and varies in accordance with features of embodiments. In someembodiments, a patterning operation patterns an existing film or layer.The patterning operation includes forming a mask on the existing film orlayer and removing the unmasked portion of the film or layer with anetch or other removal process. The mask is a photo resist or a hardmask.In some embodiments, a patterning operation directly forms a patternedlayer on a surface. The patterning operation includes forming aphotosensitive film on the surface, conducting a photolithographyprocess and a developing process. The remaining photosensitive film maybe removed or retained and integrated into the package.

The problems and needs outlined above may be addressed by embodiments ofthe present disclosure. FIG. 1 is a cross sectional view of a portion ofa semiconductor package 100 in a 2L setting. A device substrate 101includes a semiconductor substrate, such as a silicon wafer, a silicondie, a semiconductor-on-insulator (SOI) substrate, or any constructioncomprising semiconductor materials. Semiconductor devices, such astransistors, capacitors, resistors, diodes, photo-diodes, fuses, and thelike, interconnected to perform one or more functions is formed at asurface of the substrate 101. A dielectric layer or a passivation layer103 is disposed on the substrate 101 to provide electrical insulation ofthe electrical connection from the substrate 101 at some predeterminedregion. In some embodiments, the passivation layer 103 is formed of anon-organic material selected from un-doped silicate glass (USG),silicon nitride, silicon oxynitride, silicon oxide, and combinationsthereof. In another embodiment, the passivation layer 103 is formed of apolymer layer, such as an epoxy, polyimide, benzocyclobutene (BCB),polybenzoxazole (PBO), and the like, although other relatively soft,often organic, dielectric materials can also be used.

Referring to FIG. 1, a PPI layer 105 is disposed on the passivationlayer 103. In some embodiments, the PPI layer 105 is formed of aconductive material including, but not limited to, for example copper,aluminum, copper alloy, nickel, or other mobile conductive materials. Inother embodiments, the PPI layer 105 electrically connects semiconductordevices in the substrate 101 to a subsequently-formed conductivestructure 107. The PPI layer 105 also function as a power line,re-distribution line (RDL), inductor, capacitor, or any passivecomponent. In some embodiments, the PPI layer 105 has a thickness lessthan about 30 μm, for example between about 2 μm and about 25 μm. Inother embodiments the PPI layer 105 has a top surface 1057 at the sideopposite to the passivation layer 103. The conductive structure 107 iselectrically coupled to the PPI layer 105 by connecting to the topsurface 1057 of the PPI layer 105.

In some embodiments, the top surface 1057 of the PPI layer 105 includesa first region 1051 electrically connected to the conducive structure107, and a second region 1052 surrounding the first region 1051, notelectrically connected to the conductive structure 107. The featuredistinguishing the first region 1051 and the second region 1052 is thatthe second region 1052 includes a metal derivative layer at the topsurface 1057 of the PPI layer 105, whereas no metal derivative layer ispositioned within the first region 1051. The wetting property of thesecond region 1052 is termed with respect to the conductive structure107, which is often metallic material, and the unwetted property of thesecond region 1052 is caused by a metal derivative 1055 positionedtherein. Considering the surface energy of the metal derivative 1055 andthe surface energy of the conductive structure 107, the contact betweenboth the metal derivative 1055 and the conductive structure 107interface exert a repelling force on each other. In other words, acontact angle (not shown) of the conductive structure 107 to the metalderivative 1055 is as least greater than 90 degrees, demonstrating a lowwetting capability.

In some embodiments, the conductive structure 107 includes a copperlayer, a copper alloy layer, a nickel layer, a nickel alloy layer, asolder layer, or combinations thereof. The solder layer in theconductive structure 107 may include a lead-free pre-solder layer, SnAg,or a solder material including alloys of tin, lead, silver, copper,nickel, bismuth, or combinations thereof. In certain embodiments, theconductive structure 107 is a solder ball or a solder paste. Forexample, the use of lead in solder composition has come under scrutinyand has become undesirable for environmental and health reasons. As aresult, in some embodiments, the solder ball is to eliminate therequirement for lead from solder compositions. Such lead-free soldercompositions typically include tin, copper and silver (typically 95.5%by weight tin, 4% by weight silver and 0.5% by weight copper). Bismuthmay also be used together with tin, antimony and silver in a range ofapproximately 1.0% to 4.5% by weight.

Referring to FIG. 1, although not shown in the final product asdemonstrated in the semiconductor package structure 100, a flux materialis predisposed between the conductive structure 107 and the first region1051 of the PPI layer 105 before a reflow operation. It has beengenerally recognized that providing a flux material which achieves anumber of functions is desirable. In particular it is desirable that theflux material provides good surface activation. In this respect, it hasbeen known to include an activator component within the flux materialwhich will act to remove oxidized material from a metal surface, therebyallowing better solder to metal interconnection. In some embodiments,activators are added to decompose and remove any oxide film existing inthe portion where soldering is going to be carried out, and are usuallyorganic compounds containing halides, typically amine hydrohalides, suchas diethylamine hydrochloride or weak halide-free organic acids.

In some embodiments, the metal derivative 1055 possess a thickness Tfrom about 1 μm to about 3 μm. Said thickness T range exceeds athickness (not shown) of the native oxide or nitride at the top surface1057 of the PPI layer 105, depending in which ambient environment thepackaging operations are carried out. In some embodiments, the PPI layer105 is formed of a conductive material including, but not limited to,copper, aluminum, copper alloy, nickel, or other mobile conductivematerials, and the packaging operation is conducted in anoxygen-containing environment, the metal derivative 1055 includeconductive material oxides. In other embodiments, the PPI layer 105 isformed of a conductive material and the packaging operation is conductedin a nitrogen-containing environment, the metal derivative 1055 includeconductive material nitrides.

Referring to FIG. 2A, FIG. 2A is a top view of the semiconductor packagestructure 100 shown in FIG. 1 according to some embodiments of thepresent disclosure. Elements sharing the same labeling numerals as thosein the FIG. 1 are referred thereto and are not repeated here forsimplicity. In FIG. 2A, only the conductive structure 107 and the metalderivative 1055 are shown from a top view perspective, and theunderlying PPI layer 105, the passivation layer 103, and the substrate101 shown in FIG. 1 are covered by the conductive structure 107 and themetal derivative 1055. In some embodiments, because the conductivestructure 107 is a solder ball, a circular area having a diameter D ofthe solder ball appears to be greater than an area of the first region1051 (shown in dotted line) at the surface 1057 of the PPI layer 105.Area other than the first region 1051 is the second region 1052 definedby the metal derivative 1055. In other embodiments, the contour of thefirst region 1051 is not limited to a circular shape as shown in FIG.2A, other contours such as a square, a quadrilateral shape, or shapeswith irregular boundaries are within the contemplated scope of thepresent disclosure.

Referring to FIG. 2B, FIG. 2B is a top view of the semiconductor packagestructure 100 shown in FIG. 1 according to some embodiments of thepresent disclosure. Elements sharing the same labeling numerals as thosein the FIG. 1 are referred thereto and are not repeated here forsimplicity. In FIG. 2B, the conductive structure 107, the metalderivative 1055, and the PPI layer 105 are shown from a top viewperspective, and the underlying passivation layer 103 as well as thesubstrate 101 shown in FIG. 1 are covered by the conductive structure107, the metal derivative 1055, and the PPI layer 105. Considering themetal derivative 1055 is non electrical conductive and therebyincreasing the resistance of the PPI layer 1055, the second region 1052defined by the metal derivative 1055 is shrinked to a smaller areasurrounding the first region 1051 compared to that shown in FIG. 2A. Inother embodiments, the contour of the metal derivative 1055 is notlimited to a square shape as shown in FIG. 2B, other contours such as acircle, a quadrilateral shape, or shapes with irregular boundaries arewithin the contemplated scope of the present disclosure. In still otherembodiments, the contour of the metal derivative 1055 is not limited toa solid shape as shown in FIG. 2B, a discontinuous pattern such as aradiation pattern or spiral pattern of the metal derivative 1055 arewithin the contemplated scope of the present disclosure.

FIG. 3A to FIG. 9B show operations of a method for manufacturing asemiconductor package. Three alternatives are discussed in FIG. 3A toFIG. 9B, that is, operations for three embodiments are shown in FIG. 3Ato FIG. 9B. A first operation is described using FIG. 3A, FIG. 4A, FIG.5A, FIG. 6A, FIG. 7A, and FIG. 7B; a second operation is described usingFIG. 3B, FIG. 4B, FIG. 5B, FIG. 6B, FIG. 8A, and FIG. 8B; and a thirdoperation is described using FIG. 3C, FIG. 4C, FIG. 5C, FIG. 6C, FIG.9A, and FIG. 9B. Referring to FIG. 3A, a hard mask layer 301A ispositioned over a stack shown in FIG. 1 of the present disclosure. Thestack includes a substrate 101, a passivation layer 103, and a PPI layer105. In FIG. 3A, a photoresist 301A is patterned on the upmost PPI layer105 to shelter a portion of the PPI 105. However, in other embodiments,a dielectric layer is used to shelter the portion of the PPI 105. Thedielectric material including silicon nitride, silicon carbide, siliconcarbonitride, silicon oxycarbide, tetra-ethyl-ortho-silicate (TEOS)oxide, silicon oxide, multi-layers thereof and/or combinations thereofby PECVD techniques or high-density plasma CVD (HDPCVD), or the like.

Referring to FIG. 3B, a hard mask layer 301B is positioned over a stack(101, 103, 105) shown in FIG. 1 of the present disclosure. In someembodiments, the hard mask layer 301B is utilized to obtain asemiconductor package structure as shown in FIG. 2A, in which the metalderivative 1055 is blanket formed surrounding the first region 1051. Insome embodiments, the hard mask layer 301B is a first stencil platepositioned over the PPI layer 105 to shelter a portion of the PPI 105.In certain embodiments, a gap G between a bottom surface 3013 of thehard mask layer 301B and the top surface 1057 of the PPI layer 105 isless than 10 μm.

Referring to FIG. 3C, a hard mask layer 301C is positioned over a stack(101, 103, 105) shown in FIG. 1 of the present disclosure. In someembodiments, the hard mask layer 301C is utilized to obtain asemiconductor package structure as shown in FIG. 2B, in which the metalderivative 1055 is formed only at specific regions surrounding the firstregion 1051. In some embodiments, the hard mask layer 301C is a firststencil plate positioned over the PPI layer 105 to shelter a portion ofthe PPI 105. In certain embodiments, a gap G′ between a bottom surfaceof the hard mask layer 301C and the top surface 1057 of the PPI layer105 is less than 10 μm. However, in other embodiments, a coating layer(not shown) is formed at the bottom surface 3015 of the hard mask layer301C, and said coating layer is thick enough to contact the top surface1057 of the PPI layer 105. As such, the gap G′ is eliminated if a firstbottom-coated stencil plate is used as a hard mask layer 301C. In someembodiments, the coating layer is a diamond-like carbon film, and thefirst stencil plate is formed of stainless steel.

Referring to FIG. 4A and FIG. 5A, a surface treatment operation isadopted to form a metal derivative 1055 in a second region 1052 of thePPI layer 105. In some embodiments, the metal derivative 1055 is formedat a near-surface region not covered by the hard mask layer 301A that ispositioned on the top surface 1057 of the PPI layer 105, and saidnear-surface region is the second region 1052. For example, oxygenplasma 303A is adopted to convert the second region 1052 from conductivematerials to conductive material oxides. In some embodiments, the oxygenplasma 301A source is not limited to a low frequency plasma sources.Other plasma sources such as radio frequency (RF) plasma source,microwave (MW) remote plasma source, direct current (DC) plasma source,inductively coupled plasma source (ICP), electron cyclotron resonanceplasma source (ECR), and other types of plasma equipment and processescan be employed as well. Through routine experimentation, one skilled inthe art can select proper plasma equipment and conditions, such asplasma power, processing time, oxygen flow, and pressure in the chamber,required to convert the desired thicknesses of the conductive materialsinto conductive material oxides by oxygen plasma conversion as describedherein.

In some embodiments as shown in FIG. 4A, the oxygen plasma 303A isgenerated in a reactive-ion-etch system with a power density of fromabout 0.1 W/cm² to about 0.6 W/cm² and an RF frequency of from about 1MHz to about 60 MHz. The oxygen flow is about from 6 to 180 SCCM, andthe oxygen partial pressure is about from 1 to 25 mTorr. About from 15to 300 seconds of process time was sufficient to render the near-surfaceregion of the PPI layer 105 into conductive material oxides with adesired thickness T of about 1.5 μm as shown in FIG. 5A.

Referring to FIG. 4B and FIG. 5B, a surface treatment operation isadopted to pattern a metal derivative 1055 in a second region 1052 ofthe PPI layer 105. In some embodiments, the metal derivative 1055 isformed at a near-surface region not covered by the hard mask layer 301Bthat is positioned over the top surface 1057 of the PPI layer 105, andsaid near-surface region is the second region 1052. For example, oxygenplasma 303B is adopted to convert the second region 1052 from conductivematerials to conductive material oxides. As shown in FIG. 5B, the metalderivative 1055 is formed at the second region 1052 as well as at aportion of the first region. In some embodiments, because the hard masklayer 301B in FIG. 4B is a stencil plate that is not physicallycontacting the top surface 1057 of the PPI layer 105, the oxygen plasma303B is then reacting with a portion of the first region 1051 andforming a metal derivative region 1055A therein. In certain embodiments,a thickness T′ of the metal derivative region 1055A is from about 0.1time to about 0.5 time of the thickness T of the metal derivative 1055.Oxygen plasma 303B adopted in FIG. 4B is previously recited in thepresent disclosure referring to the description of FIG. 4A and is notrepeated here for simplicity.

In some embodiments as shown in FIG. 4B, the oxygen plasma 303A isgenerated in a reactive-ion-etch system with a power density of aboutfrom 0.1 to 0.6 W/cm² and an RF frequency of from about 1 MHz to about60 MHz. The oxygen flow is about from 6 to 180 SCCM, and the oxygenpartial pressure is about from 1 to 25 mTorr. About from 15 to 300seconds of process time was sufficient to render the near-surface regionof the PPI layer 105 into conductive material oxides with a desiredthickness T of about 1.8 μm as shown in FIG. 5B.

Referring to FIG. 4C and FIG. 5C, a surface treatment operation isadopted to pattern a metal derivative 1055 in a second region 1052 ofthe PPI layer 105. In some embodiments, the metal derivative 1055 isformed at a near-surface region not covered by the hard mask layer 301Cthat is positioned over the top surface 1057 of the PPI layer 105, andsaid near-surface region is the second region 1052. For example, oxygenplasma 303C is adopted to convert the second region 1052 from conductivematerials to conductive material oxides. As shown in FIG. 5C, the metalderivative 1055 is formed at the second region 1052 as well as at aportion of the first region.

Referring to FIG. 4C and FIG. 5C, in some embodiments, because the hardmask layer 301C is a stencil plate that is not physically contacting thetop surface 1057 of the PPI layer 105, the oxygen plasma 303C is thenreacting with a portion of the first region 1051 and forming an metalderivative region 1055A therein. In certain embodiments, a thickness T′of the metal derivative region 1055A is from about 0.1 time to about 0.5time of the thickness T of the metal derivative 1055. Oxygen plasma 303Cadopted in FIG. 4C is previously recited in the present disclosurereferring to the description of FIG. 4A and is not repeated here forsimplicity.

Still in FIG. 4C and FIG. 5C, in some embodiments, because the hard masklayer 301C is a bottom-coated stencil plate (not shown) that isphysically contacting the top surface 1057 of the PPI layer 105, theoxygen plasma 303C is then blocked from the first region 1051 and nometal derivative region 1055A is formed therein (not illustrated in FIG.5C). In other words, only the metal derivative 1055 in the second region1052 but the metal derivative region 1055A in the first region is formedon the near-surface region of the PPI layer 105.

In some embodiments as shown in FIG. 4C, the oxygen plasma 303C isgenerated in a reactive-ion-etch system with a power density of fromabout 0.1 to about 0.6 W/cm² and an RF frequency of about from 1 MHz toabout 60 MHz. The oxygen flow is about from 6 to 180 SCCM, and theoxygen partial pressure is about from 1 to 25 mTorr. About from 15 to300 seconds of process time is sufficient to render the near-surfaceregion of the PPI layer 105 into conductive material oxides with adesired thickness T of about 2 μm as shown in FIG. 5C.

Referring to FIG. 6A, FIG. 6B, and FIG. 6C, a flux layer 302 is formedon the first region 1051 of the PPI layer 105 by a patterning operation.In some embodiments as shown in FIG. 6A to FIG. 6C, a second stencilplate (305A, 305B, 305C) is placed over the PPI layer 105 and shelteringthe second region 1052 thereof. A squeegee (not shown) is then spreadingthe flux material into the openings of the second stencil plate (305A,305B, 305C) to form the flux layer 302. In certain embodiments, thesecond stencil plate (305A, 305B, 305C) is not limited to be locatedabove the top surface 1057 of the PPI layer 105, but rather is directlyplaced on the top surface 1057 of the PPI layer 105. In otherembodiments, the second stencil plate (305A, 305B, 305C) is abottom-coated stencil plate which is physically in contact with the topsurface 1057 of the PPI layer 105. The structure and the materials ofthe bottom-coated stencil plate is previously recited in the presentdisclosure referring to the description in FIG. 3C and is not repeatedhere for simplicity.

FIG. 7A to FIG. 9B show a solder ball-dropping operation and asubsequent reflowing operation in some embodiments provided in thepresent disclosure. Elements sharing the same labeling numerals as thosein the FIG. 1 are referred thereto and are not repeated here forsimplicity. FIG. 7A shows a conductive structure 307A such as a solderball being placed on the flux layer 302 following the operations shownin FIG. 3A, FIG. 4A, FIG. 5A, and FIG. 6A. FIG. 7B shows a finalstructure after a reflow operation conducted on the semiconductorpackage structure in FIG. 7A. In some embodiments the reflow operationincludes heating the semiconductor package structure to a temperature ofabout 250 degrees Celsius and keep at said temperature for 2 minutes.After the reflow operation is completed, the flux layer 302 disappearsand the conductive structure 307A is electrically connected to the PPIlayer 105.

FIG. 8A shows a conductive structure 307B such as a solder ball beingplaced on the flux layer 302 following the operations shown in FIG. 3B,FIG. 4B, FIG. 5B, and FIG. 6B. FIG. 8B shows a final structure after areflow operation conducted on the semiconductor package structure inFIG. 8A. In some embodiments the reflow operation includes heating thesemiconductor package structure to a temperature of about 230 degreesCelsius and keep at said temperature for 1.5 minutes. After the reflowoperation is completed, the flux layer 302 disappears and the conductivestructure 307B is electrically connected to the PPI layer 105.

FIG. 9A shows a conductive structure 307C such as a solder ball beingplaced on the flux layer 302 following the operations shown in FIG. 3C,FIG. 4C, FIG. 5C, and FIG. 6C. FIG. 9B shows a final structure after areflow operation conducted on the semiconductor package structure inFIG. 9A. In some embodiments the reflow operation includes heating thesemiconductor package structure to a temperature of about 260 degreesCelsius and keep at said temperature for 1 minute. After the reflowoperation is completed, the flux layer 302 disappears and the conductivestructure 307C is electrically connected to the PPI layer 105.

FIG. 10 to FIG. 15 show a method for manufacturing a semiconductorpackage 200 according to some embodiments of the present disclosure.Elements sharing the same labeling numerals as those in previous figuresare referred thereto and are not repeated here for simplicity. Referringto FIG. 10, a first flux layer 302 is formed on the top surface 1057 ofthe PPI layer 105. In some embodiments, the first flux layer 302 isformed using a first stencil plate 301A. As shown in FIG. 10, an opening301′ of the first stencil plate 301A has a width W1 which allows theflux paste to be positioned on the underlying top surface 1057 when asqueegee (not shown) spreading the flux paste across the opening 301′.In other embodiments, the pattering of the first flux layer 302 iscarried out by a screen printing operation or a photolithographyoperation using either photoresist or a hard mask layer.

Referring to FIG. 11, a portion of the top surface 1057 of the PPI layer105 that is uncovered by the first flux layer 302 is transformed into anunwetted layer composed of metal derivative 1055 such as conductivematerial oxides or nitrides. In some embodiments, the semiconductorpackage 200A is positioned in an oxygen-containing environment and issubject to a first temperature heat treatment. For example, the firsttemperature is of form about 100 to about 250 degrees Celsius, and theoxygen gas in the oxygen-containing environment reacts with thenear-surface region of the PPI layer 105 for a duration of about 10minutes to form a layer of metal derivative 1055. In some embodiments,the oxidation operation includes flowing oxygen gas into a chamberaccommodating the semiconductor package 200A at a flow rate of 50 SCCMand at a temperature within the range of the first temperature. In someembodiments, the metal derivative 1055 possess a thickness T of about 1μm.

However, in other embodiments, the semiconductor package 200A is subjectto an oxygen plasma treatment in an RIE chamber and the temperature insaid chamber is controlled at a first temperature. For example, thefirst temperature is of form about 150 to about 200 degrees Celsius. Insome embodiments, oxygen plasma treatment adopted in FIG. 11 ispreviously recited in the present disclosure referring to thedescription of FIG. 4A and is not repeated here for simplicity. In someembodiments as shown in FIG. 11, oxygen plasma is generated in an RIEsystem with a power density of from about 0.1 to about 0.6 W/cm² and anRF frequency of from about 1 MHz to about 60 MHz. The oxygen flow rateis about from 6 to 180 SCCM, and the oxygen partial pressure is fromabout 1 to about 25 mTorr. About from 15 to 300 seconds of process timeunder the first temperature is sufficient to render the near-surfaceregion of the PPI layer 105 into conductive material oxides with adesired thickness T. In other embodiments, oxygen plasma treatment isconducted without controlling an RIE chamber temperature at the firsttemperature.

As shown in FIG. 10 and FIG. 11, a width of the flux layer 302transforms from a width W1 to a width W2 when the metal derivative 1055is formed on the top surface 1057 of the PPI layer 105. In someembodiments, the width W2 is greater than the width W1. For example, theflux layer 302 is composed of rosin which is a mixture of organic acids(resin acids, predominantly abietic acid, with pimaric acid, isopimaricacid, neoabietic acid, dihydroabietic acid, and dehydroabietic acid).The flux layer 302 turns liquid, ionic and mildly reactive to metaloxides at molten state. The flux layer 302 tends to soften when it issubject to the first temperature (form about 150 to about 200 degreesCelsius) and is able to dissolve thinner layers of surface oxides fromcopper without further additives. Hence, the width W2 of the flux layer302 in FIG. 11 is greater than the width W1 of the flux layer 302 inFIG. 10 is because of the softening phenomenon of the rosin when it issubject to a temperature greater than 70 degrees Celsius.

Referring to FIG. 11 and FIG. 12, the first flux layer 302 is removedand a first region 1051 on the top surface 1057 of the PPI layer 105 isexposed. In some embodiments, the first flux layer 302 is removed byflux remover such as halogen-free organic solvent, amine-basedcompounds, or chelating agent having no amino group, and water in abasic environment. Compared to the width W1 of the first flux layer 302shown in FIG. 10, the width W2 of the first region 1051 in FIG. 12reflects a dimension of the first flux layer 302 after the firsttemperature treatment as shown in FIG. 11, and hence, the width W2 ofthe first region 1051 is greater than the width W1 of the first fluxlayer 302 shown in FIG. 10. In some embodiments, an area of the firstregion 1051 is greater than an area covered by the first flux layer 302in FIG. 10 before transforming the portion of the top surface of the PPIuncovered by the first flux layer into metal derivative 1055.

Referring to FIG. 13, a second flux layer 303 having a width W1 isformed on the top surface 1057 of the PPI layer 105. In someembodiments, the second flux layer 303 is formed using a second stencilplate 305A. As shown in FIG. 13, an opening 301′ of the second stencilplate 305A has a width W1 which allows the flux paste to be positionedon the underlying top surface 1057 when a squeegee (not shown) spreadingthe flux paste across the opening 301′. In other embodiments, thepattering of the second flux layer 303 is carried out by a screenprinting operation or a photolithography operation using eitherphotoresist or a hard mask layer. In some embodiments, the width W2 ofthe first region 1051 is greater than the width W1 of the second fluxlayer 303. However, in other embodiments, the width W1 of the secondflux layer 303 can be equal to the width W2 of the first region 1051.

FIG. 14 shows a conductive structure 307 such as a solder ball beingplaced on the second flux layer 303 following the operations shown inFIG. 10 to FIG. 13. FIG. 15 shows a final structure after a reflowoperation conducted on the semiconductor package structure in FIG. 14.In some embodiments the reflow operation includes heating thesemiconductor package structure to a second temperature of from about230 to about 270 degrees Celsius and keep at said temperature for 1.5minutes. After the reflow operation is completed, the second flux layer303 disappears and the conductive structure 307 is electricallyconnected to the PPI layer 105. In some embodiments, the secondtemperature is a solder reflow temperature ranging from about 230 toabout 270 degrees Celsius. Compared to the first temperature discussedpreviously where in some embodiments, the first temperature of fromabout 130 to about 220 degrees Celsius is applied to facilitate theoxidation operation and causing the first flux layer 302 to soften.

FIG. 16 shows a semiconductor package including a semiconductor packagestructure 100 as shown in FIG. 1 and an external device 201 electricallyconnected to the stack (101, 103, 105) via the conductive structure 307.The semiconductor package shown in FIG. 16 includes performing anotherreflow operation to form an electrical connection between the externaldevice 201 and the conductive structure 307. In some embodiments, thereflow operation includes heating the semiconductor package to a secondtemperature of from about 230 to about 270 degrees Celsius and keep atsaid temperature for 1.5 minutes. In some embodiments, the externaldevice 201 includes, but not limited to, a PCB board, a memory device, aCPU, or other devices possessing electrical I/O.

Some embodiments of the present disclosure provide a semiconductorpackage. The semiconductor package includes a substrate, a passivationlayer over the substrate, a post-passivation interconnect (PPI) having atop surface, positioning over the passivation layer; and a conductivestructure electrically connected to the PPI. The top surface of the PPIincludes a first region receiving the conductive structure, and a secondregion surrounding the first region. The second region includes metalderivative transformed from materials made of the first region.

In some embodiments of the present disclosure, the metal derivative ofthe second region of the semiconductor package includes metal oxides ormetal nitrides.

In some embodiments of the present disclosure, the PPI of thesemiconductor package include a power line, a redistribution line, aninductor, a capacitor, or passive components.

In some embodiments of the present disclosure, the PPI of thesemiconductor package includes conductive materials, and wherein themetal derivative of the second region comprises conductive materialoxides.

In some embodiments of the present disclosure, the conductive structureincludes a solder bump.

In some embodiments of the present disclosure, the semiconductor packagefurther comprising an external device electrically connected to theconductive structure.

Some embodiments of the present disclosure provide a semiconductorpackage. The semiconductor package includes a substrate, a passivationlayer over the substrate, a post-passivation interconnect (PPI) having atop surface, positioning over the passivation layer; and a conductivestructure electrically connected to the PPI. The top surface of the PPIincludes a first region electrically connected to the conductivestructure, and a second region surrounding the first region. The secondregion includes metal derivative with a thickness greater than about 1μm, and the conductive structure is unwetting on the second region.

In some embodiments of the present disclosure, the metal derivative ofthe semiconductor package includes oxides or nitrides.

In some embodiments of the present disclosure, the PPI of thesemiconductor package include a power line, a redistribution line, aninductor, a capacitor, or passive components.

In some embodiments of the present disclosure, the PPI of thesemiconductor package includes conductive materials, and wherein themetal derivative of the second region comprises conductive materialoxides.

In some embodiments of the present disclosure, the conductive structureincludes a solder bump.

In some embodiments of the present disclosure, the semiconductor packagefurther comprising an external device electrically connected to theconductive structure.

Some embodiments of the present disclosure provide a method ofmanufacturing a semiconductor package. The method includes patterning ametal derivative in a second region of a post-passivation interconnect(PPI); forming a flux layer in a first region of the PPI, wherein thefirst region is surrounded by the second region; dropping a solder ballon the flux layer; and forming electrical connection between the solderball and the PPI.

In some embodiments of the present disclosure, the patterning the metalderivative in the second region of the PPI of the method ofmanufacturing a semiconductor package further includes forming a masklayer over the PPI.

In some embodiments of the present disclosure, the forming the masklayer over the PPI of the method of manufacturing a semiconductorpackage further includes positioning a first stencil plate over the PPI.

In some embodiments of the present disclosure, the patterning the metalderivative in the second region of the PPI of the method ofmanufacturing a semiconductor package includes an oxygen plasma surfacetreatment.

In some embodiments of the present disclosure, the forming the fluxlayer in the first region of the PPI of the method of manufacturing asemiconductor package includes positioning a second stencil plate overthe PPI.

In some embodiments of the present disclosure, the forming the masklayer over the PPI of the method of manufacturing a semiconductorpackage further includes forming a mask layer on the PPI.

In some embodiments of the present disclosure, the forming electricalconnection between the solder ball and the PPI of the method ofmanufacturing a semiconductor package includes a reflow operation.

Some embodiments of the present disclosure provide a method ofmanufacturing a semiconductor package. The method includes forming afirst flux layer covering a portion of a top surface of apost-passivation interconnect (PPI); transforming a portion of the topsurface of the PPI uncovered by the first flux layer into a metalderivative layer; removing the first flux layer thereby exposing a firstregion of the PPI; forming a second flux layer on the first region ofthe PPI; dropping a solder ball on the flux layer; and formingelectrical connection between the solder ball and the PPI.

In some embodiments of the present disclosure, the forming the firstflux layer covering a portion of a top surface of the PPI of the methodof manufacturing a semiconductor package includes positioning a firststencil plate over the PPI.

In some embodiments of the present disclosure, the transforming aportion of the top surface of the PPI uncovered by the first flux layerinto the metal derivative layer of the method of manufacturing asemiconductor package includes heating the semiconductor package to afirst temperature.

In some embodiments of the present disclosure, the forming electricalconnection between the solder ball and the PPI of the method ofmanufacturing a semiconductor package includes heating the semiconductorpackage to a second temperature, and wherein the second temperature ishigher than the first temperature.

In some embodiments of the present disclosure, an area of the portion ofthe top surface of the PPI covered by the first flux layer beforetransforming the portion of the top surface of the PPI uncovered by thefirst flux layer into a metal derivative layer is smaller than an areaof the first region.

In some embodiments of the present disclosure, the transforming aportion of the top surface of the PPI uncovered by the first flux layerinto the metal derivative layer of the method of manufacturing asemiconductor package includes flowing oxygen into a chamberaccommodating the semiconductor package.

In some embodiments of the present disclosure, the transforming aportion of the top surface of the PPI uncovered by the first flux layerinto the metal derivative layer of the PPI of the method ofmanufacturing a semiconductor package includes an oxygen plasma surfacetreatment.

In some embodiments of the present disclosure, the forming the secondflux layer on the first region of the PPI of the method of manufacturinga semiconductor package includes positioning a second stencil plate overthe PPI.

Although the present invention and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations cancan be made herein without departing from the spirit andscope of the invention as defined by the appended claims. For example,many of the processes discussed above cancan be implemented in differentmethodologies and replaced by other processes, or a combination thereof.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A method of manufacturing a semiconductorpackage, comprising: patterning a metal derivative in a second region ofa post-passivation interconnect (PPI) by covering a first region of thePPI with a photoresist, the first region being surrounded by the secondregion; forming a flux layer in the first region of the PPI; dropping asolder ball on the flux layer; and forming electrical connection betweenthe solder ball and the PPI.
 2. The method of manufacturing asemiconductor package in claim 1, wherein the patterning the metalderivative in the second region of the PPI further comprising forming amask layer over the PPI.
 3. The method of manufacturing a semiconductorpackage in claim 2, wherein the forming the mask layer over the PPIcomprises forming a mask layer on the PPI.
 4. The method ofmanufacturing a semiconductor package in claim 2, wherein the formingthe mask layer over the PPI comprises positioning a first stencil plateover the PPI.
 5. The method of manufacturing a semiconductor package inclaim 1, wherein the patterning the metal derivative in the secondregion of the PPI comprises an oxygen plasma surface treatment.
 6. Themethod of manufacturing a semiconductor package in claim 1, wherein theforming the flux layer in the first region of the PPI comprisespositioning a second stencil plate over the PPI.
 7. The method ofmanufacturing a semiconductor package in claim 1, wherein the formingelectrical connection between the solder ball and the PPI comprises areflow operation to form a solder bump.
 8. The method of manufacturing asemiconductor package in claim 7, further comprising forming anelectrical connection between an external device and the solder bump. 9.A method of manufacturing a semiconductor package, comprising:patterning a metal derivative having a thickness of from about 1 μm toabout 3 μm in a second region of a post-passivation interconnect (PPI)by an oxygen plasma surface treatment; disposing a solder ball on afirst region of the PPI, wherein the first region is surrounded by thesecond region; forming electrical connection between the solder ball andthe PPI.
 10. The method of manufacturing a semiconductor package inclaim 9, wherein the patterning the metal derivative comprises applyinga photoresist over and in contact with the PPI.
 11. The method ofmanufacturing a semiconductor package in claim 9, wherein the patterningthe metal derivative comprises applying a stencil plate over but free ofcontact with the PPI.
 12. The method of manufacturing a semiconductorpackage in claim 9, further comprising forming a flux layer on the firstregion of the PPI.
 13. The method of manufacturing a semiconductorpackage in claim 12, wherein the forming the flux layer comprises ascreen printing operation or a photolithography operation.
 14. Themethod of manufacturing a semiconductor package in claim 12, wherein awidth of the flux layer as formed is narrower than a width of the firstregion.
 15. A method of manufacturing a semiconductor package,comprising: patterning a second region of a post-passivationinterconnect (PPI) by applying an oxygen plasma surface treatment over amask layer; annealing the PPI with a first temperature heat treatment;and forming a flux layer in a first region of the PPI, wherein the firstregion is surrounded by the second region.
 16. The method ofmanufacturing a semiconductor package in claim 15, wherein the firsttemperature is from about 100 to about 250 degrees Celsius.
 17. Themethod of manufacturing a semiconductor package in claim 15, wherein theannealing the PPI is performed concurrently with applying the oxygenplasma surface treatment.
 18. The method of manufacturing asemiconductor package in claim 15, further comprising applying the firsttemperature at the forming the flux layer in the first region of thePPI.
 19. The method of manufacturing a semiconductor package in claim15, wherein the forming the flux layer comprises patterning by a stencilplate.
 20. The method of manufacturing a semiconductor package in claim19, wherein a width of an opening on the stencil plate is narrower thana width of the flux layer patterned by the opening under the firsttemperature.